BT DUET 50, 80, 100, 200 & 200 Plus


The BT Duet range of telephones consists of four models; the 50, 80, 100 and 200.

All models are available on sale or rental terms.

The slim style 100 comprises a handset and base unit with the keys and LCD housed in the handset.

The 50 is similar in design to the 100 but without LCD and a reduced facility range.

The 200 is a conventional two piece design but with LCD and facility keys housed in the handset rest.

The 80 is similar in design to the 200 but without LCD and a reduced facility range.

Features common to 100 and 200 models in the Duet range are as follows;
13 memories (up to 24 digits in length)
Liquid Crystal Display (10 digit)
Latching Secrecy Button (with LED)
Last Number Redial (24 digits)
Ringer Volume Control (Hi/Lo/Off)
Pause Facility
Switchable between pulse-earth, tone-earth and time-break recall
2 Years Guarantee

Features common to 50 and 80 models in the Duet range are as follows:
10 memories (up to 16 digits in length)
Last Number Redial (24 digits)
Ringer on/off switch
Switchable between pulse dialling or tone dialling with time-break recall only
1 Year Guarantee

duet200z.jpg (19502 bytes)Only the Duet 100 and 50 can be wall mounted. When wall mounted the handset clip should be reversed to support the handset. It's base is fitted with a protruding lug to hold the handset away from the switchhooks, to prevent the handset hanging from the cord when taking an incoming call for a third party.
Made by Inventec

Approved under Approval numbers:-
Duet 50: S/2981/3/P/502805
Duet 80: S/2981/3/P/502804
Duet 100: S/2981/3/M/502288
Duet 200: S/2981/3/M/502324

The Duet 100 and 200 is approved for use on DELs and PBXs in categories 1,3,5,7,9 & 11. Duet 50 and 80 is not approved for use on PBXS.

All telephones in the Duet range have a REN of 1 and are intended for use in normal Domestic/Residential locations. In addition Duet 100 and 200 may be connected to any approved PBX.

Approximate overall dimensions are:
Duet 50 & 100: 220mm(long) x 65mm(wide) x 73mm(high), weight 554 grams.
Duet 80 & 200: 164mm(deep) x 225mm(wide - including handset) x 63mm(high), weight 524 grams.

Two 25mm x No. 8 pan-head wood screws and wall plugs are provided for wall mounted use via key-hole slots in the base of the Duet 50 & 100.

The Signalling switch of the Duet 100 or 200 should be set on installation according to the type of exchange/PBX it is used on, i.e.;

TB - for Digital or Modernised TXE4 exchanges and a minority of PBXs (i.e. for MF, Star Services and Timed Break Recall PBXS).
T - for the majority of modern PBXs (i.e. with MF signalling with Earth recall).
P - for unmodernised exchanges and older PBXS. (pulse signalling)

Duet 50 and 80 is switchable only between P and T (pulse or tone) depending upon whether the exchange line is connected to an unmodernised pulse signalling exchange or to a modern exchange with tone signalling.


Description  BT Item Code
Duet 50
Alpine White 870630
Oatmeal 870631
Duet 80
Alpine White 870633
Oatmeal 870634
Duet 100
Alpine White - 1992 877939
Oatmeal - 1992 877940
Gentian Blue - 1992 877941
Red Earth - 1992 870649
Ocean Green - February 1994 877944
Peach - June 1992
Baltic Green - June 1992
Duet 200
Alpine White - April 1992 877945
Oatmeal - April 1992 877946
Black - April 1992 877947
Red Earth - June 1992 877948
Marble Grey 877949

Idle - Normal capacitor loop, additionally these telephones draw on-hook current (typically 10 micro Amps) to maintain stored/last number memory. This may give apparent 'Low Loop' line test conditions.
Seized - Normal press button telephone loop. The electronic keypad and transmission circuitry may give 'high resistance' tele-loop line test conditions as with other press button telephones.

Signalling details:

MF signalling
All models, continuous tone whilst button is pressed.
Timed break recall, all models, approximately 90 ms.

Earth recall
Duet 100 and 200 only, continuous whilst recall button is pressed (to a maximum of 1.35 seconds).

Duet 100 and 200 from the serial numbers below will no longer support earth recall:-
DUET 100 From Serial No. 9433000000
DUET 200 From Serial No. 9429000000 

PBX Interworking:
Some facilities are not available when Duet 100 or 200 telephones are connected to a Renown or BT2+8. Duet 50 and 80 telephones are not suitable for connection to a Renown or BT2+8.


Ideally suited to the residential market, the Duet 200 Plus is a stylishly designed and affordable corded phone with LCD. A ringer volume control allows the user to select how loud the phone rings - perfect for the noisy household and the hard of hearing.

Key Features:

  • LCD

  • Number of indirect memories - 12

  • Call timer

  • Last number redial

  • Ringer volume control

  • Mute button

  • Recall button

  • Memory without power - 5 mins

  • Time break recall

  • Tone dialling

  • REN - 1


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Last revised: December 06, 2010